Torque amplifier



Aug. 13, 1946. w W Re 22,779

' TORQUE AMPLIFIER I Origiria.l Filed Sept. 25,- 1945 'INVENTOR. M ILLARD .SW/FZJR.

.- camwam ATTORNEYS Reissuecl Aug. 13, 1946 UNITED STATES PATENT OFFICE Serial No. 503,831, September 25, 1943.

plication for reissue March 30, 1945, Serial No.

12 Claims.

The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

The present invention has for its object a torque amplifier wherein a high power input may be controlled with respect to the output torque by means of a finely variable, manually operable speed reduction device. Another object of the invention is to provide such a device wherein the direction as well as the torque of the final driven shaft may be regulated.

The driving train to the driven shaft is established through a spring coiled around the shaft and at times loosely received in a drive gear. One end of the spring is anchored to the shaft and the other end frictionally received in a member which also loosely surrounds the shaft. This member is rotated from a variable speed device to drag the sprin and, in one direction, expand it into contact with the gear. In this condition the spring i a driving connection between the gear and the shaft until the shaft exceeds the speed of the dragging member, whereupon the connection is interrupted. The connection is restored when the speed of the shaft becomes less than that of the draggin member. This cycle has a comparatively high frequency. Each cycle includes as one phase an impulse of driving force applied to the shaft. The rotation of the shaft is made substantially uniform by a device such as a flywheel or by operating parts having a flywheel effect.

A dual system of springs and driving gears is provided, the springs bein mounted in such a manner that rotation of the dragging member in one direction leaves one of the springs idle. On reversal of the variable speed device and the dragging member actuated thereby, the condition of the springs is reversed. Thus, the driven shaft may be driven in either direction.

An illustrative embodiment of the invention is disclosed in the following description and in the accompanyin drawing in which the single figure is a cross section of the device.

A drive shaft l driven from any suitable source and supported in bearings 2 carries a bevel gear 3. The bearings are mounted in asuitably shaped housing 4, and it will be understood that all bearings hereinafter mentioned are properly supported in the same housing.

A driven shaft 5 is mounted in the housing at right angles to the shaft 1. Two bevel gears or elements 6 and I are journaled in housing 4, coaxial with and about shaft 5, by antifriction (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 O. G. 757) bearings ll. These gears mesh with the gear 3 at diametrically opposite points. The gears are formed respectively with openings 8 and 9 around the shaft and receive coil springs l0 and II surrounding the shaft and having a clearance of .001 to .003 inch within their recesses 8 and 9. The springs are Wound in the same direction but have opposite ends attached to the shaft. For example, the upper end of the spring I0 is bent lengthwise at l2 and received between a pair of lugs is on the shaft, while the lower end of the spring I l is bent lengthwise at l4 and received between a pair of similar lugs 15. A spur'gear I6 is formed with or attached to the gear 5 for a purpose that will presently appear. The gears 6 and 1 are journalled in and positioned by suitable bearings I! mounted in the housing 4.

Between the springs ID and II the shaft 5 is loosely surrounded by a sleeve or member I 8 supported in suitable bearings IS. The ends of the sleeve are formed with cavities 25 and 21 receiving the inner ends of the springs H) and II in frictional engagement with the walls of the cavity. For example, the diameter of each cavity may be .001 to .002 inch smaller than the outside diameter of the spring received therein. One end of the sleeve is formed with a gear 22 fora purpose that will presently appear.

A countershaft Z3 is journalled in the housing 4 and carries the gear 24 meshing with the gear 15. A friction disk 25 is carried on the lower end of shaft 23.

Beneath the dish. a longitudinally splined shaft 26 is journalled in the housing and carries a gear 21 meshing with the gear 22. On the shaft 28 i -splined a sleeve 28 formed with a disk 29 in peripheral engagement with the disk 25. A shifting fork 30 is received in a groove 3l formed in the sleeve 28 and has a threaded stem 32 screwed in housing 4 and fitted with an operating handle 33.

In the operation of the device, the gears 6 and I are in rotation simultaneously with the drive gear 3, and a light drive is transmitted through the gears l6, 2 and disks 25, 29 :to the shaft 26 and gear 21. The speed of the latter varies with the distance of the disk 25 from the center of disk 25 and reverses when the disk 29 crosses the center of disk 25. The sleeve is is obviously driven from the gear 27 through the gear 22.

For purposes of description, it may be assumed that the parts are rotatin in the direction indicated by the arrows, the shaft 5 bei g momentarily stationary. The frictional drag on the lower end of the spring Ill against the anchored the driving connection between the gear 6 and the shaft until the cycle is repeated when the speed of the shaft drops below that of the gear 22. These cycles are ofrelatively high frequency and result in a substantially uniform speed of the shaft 5 as determined by the position of the sleeve 28. During this operation, the spring II is merely tightened on the shaft 5, so that the gear I merely overruns, and spring ll slips in pocket 2|.

On reverse rotation a similar overrunning occurs with respect to the gear 6. The spring H, however, is expanded intermittently to establish a drive between the gear 1 and the shaft 5 in the manner already described in detail.

The mechanism i well suited for installation where the desideratum is the delicate and accurate control of a high power input rather than efiiciency in transmitting power. As an example, the mechanism may be used to traverse a gun or rotate the turret of a combat tank. In such case the shaft 5 carries a take-off gear 34 that meshes with a ring gear carried by the body of the tank. Manual adjustment of the handle 33 regulates the high torque applied at the gear Sand increased through the described ear train that determines the speed of the shaft 5.

While a specific embodiment of the invention has been illustrated and described, it is intended that various alterations in the details of construction may be made without departing from the invention as indicated by the scope of the appended claims.

What I claim is:

1. A torque amplifier comprising drive and driven shafts, a revoluble element coaxial with said driven shaft, mean connecting said revoluble element to said drive shaft, a member journaled on said driven shaft, a coil spring surrounding said driven shaft and received loosely in said element; said spring having one end anchored to said driven shaft and the other end frictionally connected to said member; a variable speed device, means for driving the input of said variable speed device and means connecting the output side of said variable speed device to said member.

2. A torque amplifier comprising drive and driven shafts, a gear coaxial with said driven shaft and geared to said drive shaft, a member journaled on said driven shaft, a coil spring surrounding said driven shaft and received loosely in said gear, said spring having one end anchored to said driven shaft and the other end frictionally connected to said member, a variable speed device, means for driving the input of aid variable speed device and means connecting the output side of said variable speed device to said member to rotate the same. I

3. A torque amplifier comprising drive and driven shafts, a revoluble element independently journaled coaxial with said driven shaft, means connecting said revoluble element to said drive shaft, a gear journaled concentric of said driven shaft, a coil spring surrounding said driven shaft and received with .001 to .003" clearance in said element, said spring having one end anchored to said driven shaft and the other end frictionally fitting a counterbore in said gear, a variable speed device, means for driving the input of said variable speed device andmeans connecting the output side of said variable speed device to said gear to rotate the same.

4. A torque amplifier comprising a drive shaft, a driven shaft, a pair of rotatable elements journaled coaxially with said driven shaft, means connecting said rotatable elements to said drive shaft for rotation thereby, a member journaled coaxially with said driven shaft between said elements, a pair of coil springs surrounding said driven shaft and fitting in said respective elements with slight clearance, each of said springs having one end anchored to said driven shaft and the other end frictionally connected to said member, said springs being mounted to be respectively wound and unwound on rotation of said member in a given direction, a variable speed device, means for driving the input of said variable speed drive by and in response to operation of said driving shaft, and means drivingly connecting the output side of said variable speed device to rotate said member.

5. A torque amplifier comprising drive and driven shafts, a pair of gear journaled coaxially of said driven shaft and geared to said drive shaft, a member coaxial with said driven shaft between said gears, a pair of coil springs surrounding said driven shaft and loosely received in said gears respectively, each of said springs having one end anchored to said driven shaft and the other end frictionally connected to said member, said springs being mounted to be respectively wound and unwound on rotation of said member in a given direction, a variable speed device, means for driving the input of said variable speed device, mean connecting the output of said variable speed device to said member.

6. A torque amplifier comprising, a drive shaft, a driven shaft, an element journaled for rotation coaxially with and about said driven shaft, means connecting said element to be driven by said drive shaft, a member mounted coaxial with said driven shaft, a coil spring surrounding said driven shaft and received with small clearance in said element, said spring having one end anchored to said driven shaft and its other end frictionally connected to said member, a first friction disk,

splined shaft, gearing between said splined shaft Y able over said first disk, and means rotating said first disk by and in response to rotation of said drive shaft.

7. A torque amplifier comprising a drive shaft, a driven shaft, a rotatable element mounted coaxial with said driven shaft, means connecting said rotatable element to be rotated by said drive shaft, a member journaled concentric with said driven shaft, a coil spring surrounding said driven shaft and received with small clearance in said element, said spring having one end anchored to said driven shaft and the other end frictionally connected to said member, a first friction disk, means connecting said friction disk to be driven by said element, a splined shaft, drive means connecting said splined shaft and member to rotate the member on rotation of said splined shaft, a sleeve slidably mounted on said splined shaft, and a second disk fixed to said sleeve and frictionally engaging said first disk.

8. A torque amplifier, comprising, a drive shaft, a driven shaft, a pair of elements journaled for rotation coaxially with and about said driven shaft, means operable to oppositely rotate said elements by and proportional to rotation of said drive shaft, a member journaled for rotation coaxial with said driven shaft between said elements, a pair of coil springs surrounding said driven shaft, each being received with small clearance in a respective one of said elements, each of said springs having one end fixed to said driven shaft and its other end frictionally connected to said member, said springs being mounted to be respectively wound and unwound in response to rotation of said member in a given direction, a friction disk, a driving connection between said drive shaft and disk, a splined shaft, mean rotating said member by and in response to rotation of said splined shaft, a sleeve slidably mounted on said splined shaft, a second disk fixed to said sleeve concentric of said shaft and movable radially of and in driven contact with said first disk.

9. A torque amplifier comprising a drive shaft, a driven shaft, a pair of elements mounted for rotation coaxially with said driven shaft, means rotating said elements in opposite directions by and in response to rotation of said drive shaft, a member mounted for rotation coaxially of aid driven 6 10. A torque amplifier comprising a constant speed input shaft, a variable speed output shaft, an input gear on said input shaft, oppositely rotating drive gears surrounding the output shaft, helical springs between said output shaft and said drive gears, a control member frictionally engaging said springs, aid springs being disposed to connect said drive gears and said output shaft on bemg wound or unwound by said control member,

10 and light duty, variable speed, reversible driving means for driving said control member in either direction, and power means for driving said variable speed driving means.

11. In a torque amplifier, an input means, an

output shaft, an element and a member independently journaled coaxial with said shaft, a coil spring surrounding said shaft and being received 4 with small clearance in said element, said sprin having one end anchored to said shaft and a second end frictionally engaging said member, and

a variable speed device interposed between said input means and said member to drive the latter at a selected speed ratio by and in response to operation of said input means.

12. In a torque amplifier, an input means, an output shaft, an element independently journalecl coaxial with said shaft, a coil spring closely surrounding said shaft between said shaft and element and normally having a small clearance with said element, said spring being anchored at one said first gear to drive the same.

end to said shaft, and variable speed means driven by said input means to impositively drive the other end of said spring to cause the same to expand within and clutch said element to thereby 5 form a driving connection between said input means and shaft.

WILLARD E. SWIFT, JR. 

